Improvement in bit-stock



est.

ALBERT S. ALDEN; OF CHICOPEE, MASSACHUSETTS.

Letters Patent No. 87,816, dated M11/rch 16, 1869. i

IMPROVEMENT IN BIT-STOCK.

The Schedule referred to in these Letters Patent and making part of the sama.

To all whom 'it ma/y concern Be it known that I, ALBERT S. ALBEN, of Chicopee, Hampden county, State of Massachusetts, have invented certain new and useful Improvements in Chucks for Braces; and I do hereby declare that the following is a full and clear description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

Inthe drawings- 'l Figures I and III are detailed side views of parts of my invention;

Figures II and IV are coiresponding detail end views of the same parts; v

Figure V is a sectional side view of the whole and Figure VI is an end view of the whole.

The object of my invention is to produce a chuck for bit-braces which shall be easily operated, not liable to getout of order, and cheaply and easily manufactured.

In construction, I form my brace-head, or chuck, of

four pieces-a centre, or foundation-piece, G, a sleevefastening, A, a nut, I, and a setscrew,1.

The centre-piece O has, at its end, a square socket,

E,' tapering inwardly, to receive the shank of the bit.

The piece C is turned With a cylindrical surface extending back about one and a half inch, and upon this the sleeve A fits and works loosely. The sleeve A is intended to be moved longitudinally, as well as rot-atorially, its longitudinal movement extending about three-quarters of an inch, and its rotary movement being limited to about one-eighth turn. The stops for these movements of the sleeve are formed by means of a quadrilateral cavity, G, constructed in the surface of the piece O, a screw, 1, being put through the sleeve A, so as to project into this cavity, and stop against its sides, as the sleeve is moved either way, longitudinally or rotatorially.

The rear portion of the piece C is turned much larger than the rest, and coarse threads F are cut upon its surface, with which the corresponding threads H in the nut I'mesh.

The arrangement of this nut I is as follows:

The sleeve A, being formed with a partially-closed end, the opening consisting of a square hole, L, of sufficient size to admit the shank of the largest-sized bit,

is slid over the cylindrical part M of the centre-piece O, the flange O, on the rear end of the sleeve, forming a shoulder of nearly equal diameter to the threaded portion of the centre-piece C.

The nut I, being formed with an inward flange, P,

at its outer end, suiciently projecting to catch upon the ange O of the sleeve, is placed over it, and-slid back until its threads H engage with those upon the rear of the centre-piece. The screw 1 is now put in place, and the chuck is ready for use. The operation of securing the bit is as follows:

The square h ole L, in the end of the sleeve, is rst brought squarely opposite to the socket Ein the centrepiece, by turning the sleeve to the desired position. The

shank of the bit is then inserted in the socket E, and the sleeve A is turned one-eighth turn, the screw stopping it in the proper place. This brings the sides of the square hole L across the corners of the shank, and in a similar relative position tothe square socket E in the centre-piece, as shown in the top view, Fig. VI. The nut I is then turned until it clamps the sleeve tightly down upon the head of the bit-shank, as shown in the sectional view, Fig. V.

The screw 1 performs the double oice of forming the stop for both motions of the sleeve, and also of preventing the same from `sliding'back when there is no tool in, or when it is desired to move it out by turning the nut, it forming a shoulder for the ange of the nut at S.

The bit is taken out by merely reversing the 'move-- ment of fastening, first turning the nut until the sleeve is unclamped, and then turning the sleeve until the square hole corresponds in position to the square socket E, when the bit can be withdrawn through it.

-By this means, If obtain a chuck for braces or other similar devices, which is composed of only four simple parts, and cannot get out of repair by ordinary usage. It is more eliective, in holding the bit in place firmly, than any others in the market, in which such simple means are used, and requires no trimming of the bit,

forth.

ALBERT S. ALDEN. Witnesses:

E. H. HYDE, J. B. Grumman. 

